dbus-uuidgen [--version] [--ensure[=FILENAME]] [--get[=FILENAME]]
The dbus-uuidgen command generates or reads a universally unique ID.
Note that the D-Bus UUID has no relationship to RFC 4122 and does not
generate UUIDs compatible with that spec. Many systems have a separate
command for that (often called "uuidgen").
See http://www.freedesktop.org/software/dbus/ for more information
The primary usage of dbus-uuidgen is to run in the post-install script
of a D-Bus package like this:
This will ensure that /var/lib/dbus/machine-id exists and has the uuid
in it. It won't overwrite an existing uuid, since this id should
remain fixed for a single machine until the next reboot at least.
The important properties of the machine UUID are that 1) it remains
unchanged until the next reboot and 2) it is different for any two run-
ning instances of the OS kernel. That is, if two processes see the same
UUID, they should also see the same shared memory, UNIX domain sockets,
local X displays, localhost.localdomain resolution, process IDs, and so
If you run dbus-uuidgen with no options it just prints a new uuid made
up out of thin air.
If you run it with --get, it prints the machine UUID by default, or the
UUID in the specified file if you specify a file.
If you try to change an existing machine-id on a running system, it
will probably result in bad things happening. Don't try to change this
file. Also, don't make it the same on two different systems; it needs
to be different anytime there are two different kernels running.
The UUID should be different on two different virtual machines, because
there are two different kernels.
dir/lib/dbus/machine-id (localstatedir is usually /var). If this
file exists then it will be validated, and a failure code
returned if it contains the wrong thing. If the file does not
exist, it will be created with a new uuid in it. On success,
prints no output.
Print the version of dbus-uuidgen
Please send bug reports to the D-Bus mailing list or bug tracker, see
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